Metal foil



Patented Apr. 26, 1938 UNITED STATES PATENT OFFICE METAL FOIL No Drawing. Original application February 18.

1935, Serial N0. 7,071.

Divided and this application October 21, 1935, Serial No. 45,967 3"Claims. (CL 91-68) Our invention relates to a product which will adhere to metal and adhere to glass.

It is our object to provide a syntheticresin that has a tough, elastic and flexible body, and that is adherent to metal and to glass; and which has the further characteristics that upon being applied to metal when in solution will dry on the metal as a tough, flexible adherent coating for the metal, and will adhere to glass thereafter, upon being reheated and subjected to some degree of pressure.

It is a further object of our invention to provide a substantially transparent, tough, metaladherent, flexible material that can be applied to metal foil which is structurally weak, with the result that the metal foil is structurally strong, without losing any of its characteristics of appearance, light weight and of being impervious to moisture.

It is a further object to provide such a coating that is substantially non-hygroscopic.

It is our object to provide a new article of manufacture, such as a structurally weak metal foil and the coating of this invention to provide a resulting new product that has the characteristics of metal foil without its weakness, which can be folded and formed into packages or into labels; which can be made adherent to itself or to glass, and which will maintain the metal foil in smooth, brilliant condition as it is originally produced irrespective of being folded, pressed or sealed.

The metal foil that we refer to ranges in thickness from .00025 up to .001, but we do not desire to be confined to any particular thickness of foil. We have found that the compounds of this inventionare adherent to all types of metal. Foil that is structurally so weak as to ordinarily have to be supported by a paper backing, and which when handled has to be handled with the greatest care, can be converted into a strong tough and flexible material by the practice of the present invention.

The objection to materials for strengthening foil heretofore has been that they do not adhere; that they are water absorbent, defeating the very object of using foil for wrappers; they are brittle or very sticky. These objections have been overcome by the present invention.

Our invention consists broadly of a compound having the following characteristics:

(a) A tough body capable of being formed into (b) A film that is metal-adherent so that upon I,

being applied in a solvent condition at a predetermined temperature will dry on metal as on metal foil, and form with the foil a unitary structure so that the foil and the film cannot be detached one from the other..

(e) A flexible material that can be bent,folded and twisted without the fracture of the metal or the film made an integral part of the metal.

(cl) The sheet can be softened upon the application of heat so that it can be sealed one part to the other, or can be applied to glass by reheating and the application of slight pressure.

(8) The material has such viscosity that it has a uniform drying throughout,-without bubbles, resulting in perfect adhesion between the metal and the material or between the material and glass.

We have found that among the materials that provide for a tough body film are cellulose acetate, cellulose nitrate, vinyl acetate, vinyl acetate polymerized,.vinyl acetate modified with acetaldehyde, and various other equivalent resins that are normally flexible and hard and tough, but not adherentto metal.

We have found that substances that are adherent to metal, but which are not flexible, hard and tough are such materials as a saturated alkyd resin, coumarone-indene resin, a phenolic resin, shellac, de-waxed shellac, and gum dammar.

We have found that materials which are suitable plasticizers are chlorinated diphenyl, triphenyl phosphate, tricresyl phosphate and dibutyl phthalate. Such plasticizers are flexible and control the drying rate.

We find that the addition of linoleate of lead controls the drying rate in connection with an oxidizing substance, and the addition of waxes and stearates control the tendency of the compound in films to stick to one another, particularly where it is necessary to roll the composite foil film, after having beenproduced in the interim, before it is utilized in commerce.

Our invention consists of the combination of a tough body means and adherent means, a flexible means, together with a suitable solvent. The result is a non-hygroscopic metal and glass adherent film that can be used for the production of strong metal foil products, labels, cigarette packages and other forms of containers.

The particular problem in accomplishing this invention was the production of a compound that would adhere to the very delicate, thin metal foil with its highly polished surface without the application of pressure, or any other mechanical aids. The problem is entirely different from securing adherence to heavy metal articles, where pressure can be employed, or where the article is structurally strong and relatively inflexible.

In the case of foil that is structurally weak, the problem is greatly magnified in its difiiculties, both as to application and adherence. It is the object of this invention to provide a resulting product embodying foil that is structurally weak in a form that is structurally strong, thereby opening up an entirely virgin field for the use Example 1 2.4 grams of vinyl acetate, 6 grams. of phenolic resin, 2.5 grams of chlorinated diphenyl and 18 cc. of toluol, when applied at 105 degrees C. for three minutes to metal foil, provide a strong, tough product having a water-white brilliancy and sparkle. The product is strongly adherent to metal, and cannot be detached therefrom at room temperatures, and the metal can be attached to glass by the application of heat and slight pressure.

Example 2 Vinyl acetate and paraflin wax or tallow or lanolin applied to foil produce a metal-adherent substantially transparent coating.

Example 3 A solution of polymerized vinyl acetate in which 70 per cent. of the acetate has been replaced by acetaldehyde, when dissolved in toluol and combined with 12 per cent. tricresyl phosphate produces a compound that can be applied at 110 degrees C. and is metaladherent.

Example 4 A mixture of 65 per cent. cellulose nitrate and a saturated alkyd resin, which is a compound of phthalic or other polybasic acid, with glycerine or other polyhydric alcohol, chemically modified with non-drying fatty acids in the proportion of a modifying acid of from 28 per cent. to 37 per cent., and the base resin from 63 to 73 per cent. The temperature of coating and drying the foil is 100 degrees C., for approximately one-half hour. The surface is printable and adheres to metal foil.

Example 5 A saturated alkyd resin of '72 per cent., a modifying acid of 28 per cent., plus per cent. by volume of dibutyl phthalate. The result is a clear, water-color resin, having a slight tack, flexible and adherent to metal foils. The temperature of drying is the same as in Example 1.

Example 6 A saturated alkyd resin of '72 per cent., modifying acid of 28 per cent. with the addition of 10 per cent. by volume of dibutyl phthalate and 10 per cent. by weight of zinc stearate. The temperature of drying is the same as in Example 1.

Example 7 An alkyd type resin, modified with. natural resin acids plus 10 per cent. by weight of tung oil, dried at 105 degrees C. for one-half hour gives a clear, light amber resin, slightly tacky, flexible, with good adherence to metal.

Example 8 An alkyd type resin, plus 5 per cent. tung oil. dried at 100 degrees C., in four layers, each drying one-half hour, gives a flexible resin with good metal-adherence and no tack.

Example 9 A synthetic alkyd resin, reacted with a phenol compound, heated to 130 degrees C., twenty minutes, gives smooth, water-white, no tack, flexible, with very good metal foil adherence.

This resin is a pale solution, comprising 50 per cent. of synthetic resin and 50 per cent. xylol by weight.

Example 10 5 grams of a coumarone-indene resin polymerized, plus nitro-cellulose 6 grams, plus 2 grams refined heavy coal tar oil, heated at 110 degrees C. for 20 minutes, gives a flexible, nonvtacky coat with very good adherence to glass and metal.

Example 11 25 grams of coumarone-indene resin, polymerized; 50 grams of nitro-cellulose and 4 grams of castor oil for a metal-adherent compound.

Example 12 A phthalic resin, plus pale blown castor oil 1.9 per cent., 110 degrees C., twenty minutes, heat of adhesion 100 degrees, 0. gives adherence to glass and to metal foil.

Example 13 A saturated alkyd resin and vinyl acetate in proportions of 30 per cent. to 50 per cent. of the former and 70 per cent. to 50 per cent. of the latter, applied and dried at 110 degrees C. for fifteen minutes, gives a flexible metal-adhering and glass-adhering resin.

Example 14 Fatty acid pitch at a drying temperature of 110 degrees C., one-half hour, gives a flexible body with good adherence to glass and metal.

Example 15 A saturated alkyd resin modified with 1 per cent. of linoleate of lead as a drier, applied at 120 degrees C. for twenty-five minutes, gives a flexible coat, adhering to glass and metal.

Example 16 A saturated alkyd resin, plus 10 per cent. nitro cellulose, plus 1 per cent. linoleate of lead, at a drying temperature of 135 degrees C. for fifteen minutes gives a flexible coat with very excellent adherence to glass and metal.

Example 1? 80 grams of an alkyd resin with 20 grams of a. condensation resin of formaldehyde, with aromatic sulfonamides, 1 gram of linoleate of lead, 50 cc. toluol, 10 cc. naphtha and '10 cc. benzine gives a golden-colored, flexible compound with superior adherence to glass and metal. Temperazire of drying is 130 degrees C., for fifteen minu 8. i

Example 18 A saturated alkyd resin 89 per cent., white ceresin wax 10 per cent., linoleate of lead drier 1 per c'ent., applied at 130 degrees 0., and dried twenty-five minutes at that temperature on metal foil gives very good adherence to metal, and under re-heating and pressure applied adheres to glass.

Example 19 A saturated alkyd resin 89 per cent. carnauba wax 10 per cent., linoleate 0!. lead drier 1 per cent, -and dried at 130 degrees C. for twenty-five minutes gives a flexible, slippery coat with no tackiness on the metal foil, with very good adhesion to metal and adheres to glass with the metal on re-heating.

Example 20 A saturated alkyd resin grams, 20 grams of a condensation resin of phenol formaldehyde, with aromatic sulfonamides, lead 1 gram, 50 cc. toluol, 10 cc. solvent naphtha, 10 cc. benzine, plus 10 per cent. by weight of white ceresin wax, applied at 135 degrees C. for fifteen minutes gives a flexible foil coat with very good adherence to metal and to glass when applied with the metal under heat and pressure.

Example 21 A saturated alkyd resin 80 grams, 20 grams of a condensation resin of formaldehyde, with aromatic sulfonamides, lead 1 gram, 50 cc. toluol, 10 cc. solvent naphtha, 10 cc. benzine, plus 10 per cent. by weight of. yellow carnauba wax, applied at 135 degrees C. for fifteen minutes gives a flexible foil coat with very good adherence to metal and to glass when applied with the metal under heat and pressure.

Emmple 22 A saturated alkyd resin plus 1 per cent. linoleate of lead and 10 per cent. chlorinated rubber applied and dried at degrees C. gives a flexible film on foil with very good adherence to metal and to glass under reheating and pressure.

Example 23 A saturated alkyd resin plus 1 per cent. linoleate of lead, 10 per cent. chlorinated rubber and a condensation resin of formaldehyde with aromatic sulfonamides applied and dried at degrees C. for half an hour gives a flexible film on foil with very good adherence to metal, and to glass under reheating and pressure.

Example 24 A coumarone-indene resin 10 grams, plus a nitro-cellulose solution of 10 grams, plus 8 grams chlorinated diphenyl applied and dried at degrees C. for five minutes gives a flexible coat with good metal adherence.

Example 25 ,A saturated alkyd resin 97 per cent., parafiln oil 2 per cent., linoleate of lead 1 per cent., applied and dried at 130 degrees C. for fifteen mint on ioil with good adherence to glass and etal.

Ema ple 26 A saturated alkyd r sin and a lead drier in the proportions of 70 per cent.,' 29 per cent. and 1 per cent., respectively. The lead may vary as high as 5 mi cent. The compound is applied and dried at 130 degrees C. for fliteen to twentyfive minutes on the foil. Under reheat and pressure the foil and resin adhere to glass;

Example 27 A saturated alkyd resin, plus lead linoleate from 3 to 7 per cent, plus one-half per cent. linoleate of cobalt for surface drying, applied at and dried at 130 to degrees C. from ten minutes to one-half hour, gives a flexible, soft coat with excellent adherence to metal and glass.

Example 28 Phthalic acid-glycerol resin modified with linseed oil, when dried at 135 degrees C. for one hour, when applied to metal foil gives a clear, smooth appearance with a strong flexible resulting product.

Example 29 China-wood oil, linseed oil, malic acid and a glycerol resin, modified with rosin ester, applied at 130 degrees C. for fifteen minutes to metal foil produces a flexible product with a strong metal-adherence. If desired, tallow or parafiin wax can be added to prevent tackiness.

It will be understood we do not desire to be confined to the particular elements or products indicated, but include within the scope of our claims the equivalents thereof. The specification of percentages, temperatures and times of treatment are approximate and may be varied according to the subject-matter being treated without departing from our invention.

Our invention in this case is confined to claiming the new product, of which metal foil is a part. Cross reference is hereby made to our copending application on the material applied to the foil, Ser. No. 7070, filed Feb. 18, 1935.

It will be understood that we desire to comprehend within our invention such modifications as come within the scope of the claims and the invention.

This application is a division of our application filed Feb. 18, 1935, Ser. No. 7071.

Having thus fully described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. In combination, a sheet of metal foil and an integrally secured backing comprising coumarone-indene resin polymerized, nitrocellulose, and refined heavy coal tar oil.

2. In combination, a sheet of metal foil and an integrally secured transparent tough flexible backing which is impervious to moisture and glass and metal adherent upon reheating, said coating comprising polymerized coumarone-indene resin, nitrocellulose and refined heavy coal tar oil.

3. In combination, a sheet of metal foil and an integrally secured transparent tough flexible backing which is impervious to moisture and glass and metal adherent upon reheating, said coating comprising polymerized coumarone-indene resin, nitrocellulose and refined heavy coal tar oil, in the ratio of flve grams of coumaroneindene resin, six grams of nitrocellulose and two grams of coal tar oil.

HARVEY G. KI'I'I'REDGE. FRANK W. WILLIAMS. 

